AMBLYOPIA

Question 1

severity

Answer 1

· MILD – 0.2 - 0.3 logMAR (6/9 – 6/12)
· MODERATE - >0.3 – 0.8 logMAR (>6/12 – 6/36)
· SEVERE - >0.8 logMAR (>6/36)

Question 2

Correction of refractive error

Answer 2

Children with >+3.5DS = increased risk of amblyopia and squint

Aniso - GIVE FULL REF CORRECTION

Hypermetropia
- In accom ET – give full +
- XT or X - <+3.00 left uncorrected
- + without strabismus – give if above expected for age

Myopia - Weakest: gives best corrected VA, as myopes prefer more than weakest

Question 3

Refractive adaptation

Answer 3

PEDIG
- recommended time length to achieve max VA 18-22 weeks
- Continued VA improvement up to 30 weeks
- Considerable improv 4-12 weeks then plateus
- Resolved aniso amblyopes – range of 8-40 weeks, average 18.3 weeks

Age – more effective in younger
Duration – improv up to 24-30 weeks – greatest change in first 12 weeks
Baseline VA – Smaller improv in severe amblyopes 4-6 lines seen 6/60 starting VA
Amblyopia aetiology – ametropic very responsive – strab, aniso, combined similar outcomes from optical tx

Question 4

Patching

Answer 4

Total – occlusive patch, blender, frosted lens
Partial – bangerter foil
FT – all waking hours
PT – specific periods of time/ specific activities

Question 5

MOD AMBLYOPIA PATCHING (0.3-0.6 logMAR)

Answer 5

2 hours = 6 hours patching <7 year olds
2 hours + near tasks = better than 2 s near task

Question 6

SEVERE AMBLYOPIA PATCHING

Answer 6

6 hours = FT for <7 year olds

Question 7

Compliance for patching

Answer 7

48% of prescribed dose – better once noticing VA better
2-6 hrs = same outcome – plateaued at 4 hrs
Atropine 1%
· Paralyses the ciliary muscles to optically defocus the non amblyopic eye

· Effect lasts for longer than other cycloplegics - up to 14 days 
 
· Greater effect for near VA than distance 

Patching vs atropine – PEDIG study

Moderate amblyopia
>10 hours occlusion = quicker improv – no sig diff between all treatments at 6 months

Question 8

Optical penalisation

Answer 8

Alone or in conjunction with atropine
· Lenses used to blur VA of good eye = Use lack of rx to blur the good eye

Based on degree of amblyopia – 3 types:
Distance penalisation
· encourage amblyopic eye use in distance, +3.00DS added to non-amblyopic eye

Near penalisation
· encourage amblyopic eye use at near, cycloplegia in better eye with full Rx and adding convex lens (up to 3.00DS) to amblyopic eye

Total penalisation
· Use of amblyopic eye for all distances. Add strong convex lens to the better eye

Question 9

Indications for use optic penalisation

Answer 9

• Mild - moderate amblyopia with no co-op to patching
• VA static with other treatment
• Older children with anisometropic amblyopia - social reasons
• Latent nystagmus component

Question 10

Stimulus dep. Amblyopia

Answer 10

• Common cause = cataract
• Removal of cataract within 6 weeks uni and 10 weeks bi
• Correction with IOL or CL

Prognosis
· VA reasonable - improves if cataract acquired early infancy rather than truly congenital
· Stereopsis rare

Treatment - Intensive total occlusion ASAP after optical correction

Question 11

Strabismic Amblyopia

Answer 11

onitor N+D VA
- Explain watching for alteration with parents
- Some improv in ET angle post occlusion therapy, some not then requiring strab surgery
- Patching reduce eccentric fixation – monitor

Treatment
- Improve from FT refractive correction first
- Occlusion
- Atropine in nystagmus cases

Question 12

Recurrence
Risk factors

Answer 12

brupt stopping from long hours of patching
- Stopping therapy before 10 years
- Strabismic amblyopia
- Greater VA improv achieved
PEDIG – 42% recurrence when treatment not reduced, 14% when reduced from 6-8 hours to 2 before discontinuing

Question 13

Occlusion Amblyopia
risk factors

Answer 13

Amb in fellow eye bc of treatment
- Total occlusion
- Atropine
- After 1 week occlusion in px <18mo
- Occur up to 2 y/o

Prognosis - VA generally recovered
Treatment -Stop treatment and swap to other eye with careful supervision

Question 14

Intractable Diplopia

Answer 14

• Older children s BSV potential
• Density monitored
• Binocular function monitored

Prognosis - Unlikely to persist
Treatment - Stop treatment as first sign of diplopia , Don’t draw attention to it

Question 15

Dissociation

Answer 15

• Cases of latent/ int strabismus
• More likely >5y/o
• Px with Inadequate motor fusion
  Prognosis - Good likelihood of functional result
  Treatment
• Tx Stopped and px monitored
• May spontaneously restore bsv
• Prisms to fuse diplopia and strength reduced
• Surgery if persists
• General - Allergic response